Hot migration has been widely used in virtualization platforms (which are also known as hypervisors (HVs)), such as vSphere® available from VMware Inc. and Hyper-V® available from Microsoft Corporation.
Hot migration is a technique to transfer a virtual machine (VM) operating on a virtualization platform to another virtualization platform without interruption of the operation of the virtual machine.
For example, hot migration has been performed through the transfer of the content in a memory. In such a case, the data content of a virtual machine in a memory of a source virtualization platform is transferred to a memory of a target virtualization platform (this operation is hereinafter referred to as “memory transfer”). Upon completion of the memory transfer, the operation of the source virtual machine is switched to the operation of the target virtual machine. The memory transfer is performed through IP routing.
Nowadays, a virtual machine is hot-migrated within a single data center (DC) without stopping the operation of the virtual machine, for example, for maintenance of hardware.
The advent of cloud computing is expected to extend the distance between nodes in hot migration: for example, hot migration between Hokkaido and Kyushu and between Japan and a foreign country.
An increase in the frequency of connections among cloud environments will probably require hot migration of virtual machines over multiple cloud environments and DCs for the dispersion of the load among the DCs.
According to an aspect of the present invention, an object is to reduce the time from the occurrence of malfunction in an information processing device to the response of another information processing device.
Another object of the present invention is to achieve advantages through the configurations according to the embodiments of the present invention described below, the advantages not achievable through conventional art.
Based on such an assumption, vSphere provides a solution for long-distance hot migration referred to as Metro vMotion®.
VMware Metro vMotion can migrate a virtual machine without interruption in the operation of the virtual machine even if the round-trip delay between the virtualization platforms exceeds 5 ms.
FIG. 23 is a configuration diagram of a traditional information processing system 201.
The information processing system 201 includes data centers (DCs) 211-1, 211-2, and 211-3.
The DC 211-1 includes a gateway (GW) 212-1, a virtualization platform 213-1, and a virtual machine 214-1.
The DC 211-2 includes a GW 212-2 and a virtualization platform 213-2.
The DC 211-3 includes a GW 212-3 and a virtualization platform 213-3.
A specific DC among the multiple DCs will be indicated by one of the relevant reference signs 211-1, 211-2, and 211-3. If the DC does not need to be specified, the DC will be indicated by reference sign 211.
A specific GW among the multiple GWs will be indicated by one of the relevant reference signs 212-1, 212-2, and 212-3. If the GW does not need to be specified, the GW will be indicated by reference sign 212.
A specific virtualization platform among the multiple virtualization platforms will be indicated by one of the relevant reference signs 213-1, 213-2, and 213-3. If the virtualization platform does not need to be specified, the virtualization platform will be indicated by reference sign 213.
The DC 211, which is a data center supporting a virtualization environment, includes various computers and data communication devices (not shown).
The GW 212 connects the DC 211 to various networks. The GW 212, for example, is a general router that is representative of the DC 211.
The virtualization platform 213 includes a control program that is executed to create a virtual machine 214.
The virtualization platform 213, for example, may be Microsoft Hyper-V or VMware vSphere. Alternatively, any other virtualization platform may be used.
The virtual machine 214-1 is an emulated computer system configured in a computer. The virtual machine 214 includes an operating system (OS) and applications that operate on the virtualization platform 213. The virtual machine 214 is hot-migrated to another virtualization platform 213, as will be described below.
FIG. 24 is a flow chart illustrating a typical hot migration process performed in the information processing system 201.
In Step S201, a migration instruction is issued from an administrator to the virtualization platform 213-1.
Step S202 establishes the connection between the virtualization platforms 213-1 and 213-2.
Step S203 establishes the configuration information on the virtual machine 214-2 which is a target of migration.
Step S204 performs hot migration of the virtual machine. During the hot migration, the data content in the memory of the virtual machine 214-1 is transferred from the virtualization platform 213-1 to the virtualization platform 213-2.
Step S205 determines whether the memory content of the virtual machine 214-1 is updated and whether the memory content of the virtual machine 214-1 is transferrable from the virtualization platform 213-1 to the virtualization platform 213-2 within a predetermined threshold (for example, in 1 ms or less).
If the memory content of the virtual machine 214-1 is not updated and cannot be transferred within 1 ms (NO in Step S205), the process returns to Step S204.
If the memory content of the virtual machine 214-1 is updated or the memory content of the virtual machine 214-1 is transferrable within 1 ms (YES in Step S205), Step S206 performs last transfer on the memory from the virtualization platform 213-1 to the virtualization platform 213-2. The process (service) performed by the virtual machine 214-1 then stops, and the virtual machine 214-1 is disconnected from a common storage (not shown).
In Step S207, the migrated virtual machine 214-2 starts the process (service), and the common storage is mounted to the virtual machine 214-2.
In Step S208, the virtual machine 214-2 sends a reverse address resolution protocol (RARP) request for the update of the table in a switch (SW) (not shown).
With vMotion, the maximum round-trip delay of the transfer of a virtual machine between virtualization platforms is limited to a predetermined threshold (for example, 10 ms). Thus, the virtual machine cannot be hot-migrated over a long distance that causes a delay exceeding 10 ms.
In the example illustrated in FIG. 23, the DC 211-1 and the DC 211-2 have a low latency, that is, they are disposed close to each other. Thus, the virtual machine 214-1 of the DC 211-1 can be hot-migrated to DC 211-2 to establish the virtual machine 214-2.
The latency between the DC 211-1 and the DC 211-3 exceeds 10 ms due to a large distance therebetween. Thus, the virtual machine 214-1 of the DC 211-1 cannot be hot-migrated to the DC 211-3.